The present invention relates to a medical imaging means including a movement mechanism having a first mounting part and a second mounting part and at least three link arm assemblies, said link arm assemblies including actuator means and a link arm member or a set of link arm members, whereby said movement mechanism is used for moving a medical imaging device or a part thereof.
A great number of medical imaging methods require the movement of the imaging device or parts thereof. Such a movement can be orbital, rotational or linear. In conventional systems, the implementation of the movements requires extremely complicated arrangements.
The use of parallel-arm mechanisms is known from robotic systems for implementing a 3-dimensional movement. Such an arrangement has two essentially planar elements connected to each other by link arms or pairs of link arms of a controllable length. In the following text, such an arrangement is called a parallel-arm mechanism. One of the planar elements is fastened to a support structure, while the other planar element carries mounted thereon the means whose movement is desired. By adjusting the length of the link arms by active actuator means, a complete 3-dimensional freedom of movement is attained over spatial area needed for a specific task. Such a mechanism is commonly used in, e.g., machining equipment, aircraft simulators and placement of electronic components.
It is an object of the present invention to provide an improved medical imaging means and particularly an improved movement mechanism for use with the same.
It is a particular object of the present invention to provide an improved movement mechanism for use in conjunction with a panoramic radiography apparatus.
It is a still further particular object of the present invention to provide an improved movement mechanism for use in conjunction with a mammography apparatus.
To achieve the above-described goals and others to be mentioned later in the text, the invention is principally characterized in that
a first mounting part is adapted mountable on a support structure such as a wall, ceiling or support beam,
medical imaging device or a part thereof,
link arm members are pivotally connected at pivot points to said first mounting part and said second mounting part,
the length or position of said link arm members is adapted controllable by an actuator means, and
the position, inclination and/or rotation of said second mounting part is adapted controllable by virtue of adjusting the length of the link arm members and/or the height of their pivot point.
In the invention, the above-mentioned parallel-arm mechanism has been adapted to a novel application, namely, for implementing the trajectory of dynamically moving members in medical imaging apparatuses. No movement mechanism of a medical imaging apparatus is known in the art to be constructed using this type of parallel arm mechanism.
Medical imaging apparatuses pose extremely tight requirements on the accuracy of an arrangement implementing a trajectory. The use of a parallel-arm mechanism in such demanding applications as machining equipment has proved its capability of accomplishing an extremely precise and smooth trajectory.
The unlimited degree of freedom achievable by a parallel-arm mechanism in 3-dimensional dynamic movements over a desired area facilitates the implementation of all known imaging modes including fluoroscopy, 3D tomography, tomosynthesis imaging and slit fluoroscopy.
The use of a parallel-arm mechanism for implementing the trajectories required in a medical imaging apparatus is particularly advantageous owing to the simple construction of such a movement mechanism. Hence, the structure of the mechanism is more cost-efficient in production than conventional constructions and it is easily connectable to other parts of an imaging apparatus. The accuracy of the trajectory thus accomplished is excellent which is a significant benefit in medical imaging.